<?php
class Charset{
    /**
     * utf8
     */
    const UTF8 = "utf-8";
    /**
     * gbk
     */
    const GBK = "gbk";
    /**
     * gb2312
     */
    const GB2312 = "gb2312";
    /**
     * big5
     */
    const BIG5 = "big5";


    /**
     * 获取ContentType中的charset的值
     * @param string $contentType
     * @return string
     */


}